York P*DU-”V” User's Information, Maintenance And Service Manual

Contents

York P*DU-”V” User's Information, Maintenance And Service Manual Manual pdf 5 page image

035-19913-001 Rev. A (0404)Unitary Products Group 5Motor LubricationThe motors in these furnaces are permanently lubricated, and do notrequire periodic oiling.Every time the filters are changed the following items should be visuallyinspected:• Check combustion air and vent pipe for blockage or leakage.• Check all components to be sure they are in good condition andthat there are no obvious signs of deterioration.• Check the drain lines to make sure there are no cracks or leaks.• Check for dirt or lint on any surfaces or on components. Do not tryto clean any of the surfaces or components. Cleaning of the fur-nace and its components must be done by a qualified service pro-fessional.If, during the inspection of your furnace, you find any of the followingconditions:• Excessive amounts of dust and lint on components.• Damaged or deteriorated components or surfaces.• Leaks or blockage in the vent pipe passages.• Water on any surface inside or outside of the furnace.Do not operate the furnace, call a certified dealer / servicing contractorto check and / or clean your furnace, or for more information if you havequestions about the operation of your furnace.If all components appear to be in good operating condition, replace thefront panels. Turn ON the gas and electrical power supplies to the fur-nace, and set thermostat to the desired temperature.SECTION II: SERVICE AND MAINTENANCEMANUALSAFETY SECTIONThe following safety rules must be followed when servicing thefurnace.FURNACE MAINTENANCE SECTIONThe furnace should be cleaned and adjusted by a certified dealer orqualified service contractor once a year or before the start of everyheating season. The following items must be cleaned and serviced orreplaced if there are signs of deterioration.1. The vent terminal screen (if applicable).2. The furnace vent passageways. Should it be necessary to servicethe vent/air intake system, the manufacturer recommends this ser-vice be conducted by a qualified service agency. The operation ofthis appliance requires the reassembly and resealing of the vent/air intake system.3. The furnace burners, ignitor and flame sensor.SEQUENCE OF OPERATIONThe following describes the sequence of operation of the furnace. Referto Figure 1 for component location.1. Call for 1st stage only• On a call for 1st stage heat, the thermostat closes a circuitbetween R and W1.• The Microprocessor in the Furnace Control runs a ‘Self Check’.• The Control checks the Primary Limit, Auxiliary Limit, and Roll-out Switches for closed contacts.• The Control checks that the Low Fire Pressure Switch (1LP) isopen.• The Inducer Motor is energized on high speed, closing the con-tacts of 1LP.• The Control checks that 1LP is closed.• The Inducer is switched to low speed.• The Igniter is energized for 17 seconds.• The Gas Valve is energized on 1st Stage (Low Fire).• Flame Rectification is recognized within 7 seconds.• 30 seconds after flame is proven, the ‘Heat Low’ relay is ener-gized providing 120 Volts AC to the Blower Motor.• At the same time, the EAC and Hum Hot relays are energized,providing 120 Volts AC to the EAC Hot and Hum Hot terminals.2. Call for 2nd Stage after 1st Stage is operating• A call for 2nd Stage can be made by a 2-Stage thermostat, or bythe Second-Stage timer that comes installed in the furnace.NOTE: When using a 2-Stage thermostat, the Timer should be discon-nected.• The Inducer Motor is shifted to high speed by the control, closingthe contacts of 2LP (The High Fire Pressure Switch.).• The Control checks that 2LP is closed.• The Gas Valve is energized on 2nd Stage (High Fire).• The Control simultaneously de-energizes the Heat Low relayand energizes the Heat High relay, providing 120 Volts AC to adifferent speed of the Blower Motor.3. 2nd Stage is satisfied, 1st Stage still calling.• If a Single Stage Thermostat and the 2nd Stage Timer are used,the Furnace will stay on High Fire until the thermostat is satis-fied.• When the circuit between R and W2 is opened, the Controlswitches the Inducer Motor to low speed, causing the contacts of2LP to open.• When 2LP opens, 2nd Stage of the Gas Valve is de-energized.• 30 seconds later, the Control switches the Blower from HeatHigh to Heat Low.4. 1st Stage Satisfied• The Thermostat opens the circuit between R and W1• Immediately the Gas Valve is de-energized and Flame Rectifica-tion is lost.• The Inducer Motor is de-energized after a 15 second Post Purgeand the Hum Hot terminal is de-energized.• The ‘Fan Off Delay’ circuit is initiated. The Delay time can befield set at 60, 90, 120, or 180 seconds. It comes from the fac-tory set at 60 seconds.• The Heat Low terminal is de-energized; stopping the Blower andthe EAC terminal is de-energized.5. 1st and 2nd Stage called simultaneously• The 1st stage call is processed as described in paragraph 1above.• Once Flame Rectification is established, 2nd Stage is enteredimmediately as described in paragraph 2 above.ELECTRIC SHOCK, FIRE OR EXPLOSION HAZARDFailure to follow safety warnings exactly could result indangerous operation, serious injury, death or propertydamage.Improper servicing could result in dangerous operation,serious injury, and death or property damage.• Before servicing, disconnect all electrical power to the fur-nace.• When servicing controls, label all wires prior to disconnect-ing. Reconnect wires correctly.• Verify proper operation after servicing.